Cryogenic reservoir

DETAILED DESCRIPTION What is claimed is: 1.
A cryogenic reservoir comprising an internal reservoir (2) with a filling-emptying neck (3), an external reservoir (5) forming an envelope spaced from said internal reservoir (2), a conduit (12) extending through the external reservoir (5) and comprising an outward flaring providing a seat (14) for a sealing ring (15) of a plug valve (17) maintained in a closed position by an insulating vacuum created in an intermediate space (11) between the internal and external reservoirs (2 and 5), and a gas trapping agent in the intermediate vacuum space, wherein the trapping agent (20) is disposed in a recess (19) of the plug-valve (17) which communicates with said intermediate space through a retaining wall (21) permeable to the gases.
2.
A cryogenic reservoir according to claim 1, wherein the retaining wall (21) is a grill.




Description:
The present invention relates to a cryogenic reservoir, of the type comprising an internal reservoir with a filling-emptying neck and an external reservoir forming an envelope at a distance from said internal reservoir, a conduit through said external reservoir which flares outwardly forming a seat for a joint of a plug-valve maintained in closing position by the insulating vacuum created in the intermediate space between the internal and external reservoirs, and a trapping agent for gas of the "getter" type in said intermediate space under vacuum.
The trapping agent for the gases serves essentially to maintain a satisfactory vacuum to ensure thermal insulation of the internal reservoir, while the metals forming the internal reservoir and the reservoir-envelope have a tendency to desorb certain gases, which even in very small quantity can decrease the quality of the vacuum initially established.
The plug-valve serves on the one hand to close the evacuation passage of the gases after the vacuum has been established and also as a safety valve in the case of accidental overpressure in the intermediate space, which results from a loss of cryogenic fluid through the internal reservoir, which would vaporize very rapidly in contact with the warm wall of the external reservoir